Ripper blade for use on hydraulic arm and method for storage tank demolition

ABSTRACT

A hydraulically-operated ripper tool mounted as an attachment on a hydraulic arm of a carrier or excavator is used for demolition of large metal walled structures such as storage tanks in a very short time. The ripper tool has a sharp point for punching entry holes into the tank walls, so that no torch cutting of entry holes needs to be used, particularly where there might be volatile residues left in the tank. The ripper tool has a concave, sharp inner edge and is operated by the hydraulic arm in reciprocation so as to provide a shearing force to cut quickly through metal walls in “can-opener” fashion. The ripper tool facilitates making long vertical cuts into the tank wall from top to bottom, so that a series of vertical cuts can be made to weaken a side of the tank and allow the top of the tank structure to be brought down.

This divisional U.S. Patent Application claims the benefit of thepriority filing date of U.S. patent application Ser. No. 11/530,431,filed on Sep. 8, 2006, by the same inventors, now issued as U.S. Pat.No. 7,587,842.

TECHNICAL FIELD

This invention relates to hydraulically-powered equipment and tools forheavy construction work, and particularly, to equipment and a method forstorage tank demolition.

BACKGROUND OF INVENTION

Industrial storage tanks are widely used to store liquid fuels,chemicals, feed stocks, slurries, aggregates, etc. Such structures canbe many stories in height, e.g., 50 feet high, several hundred feet incircumference, and made of steel, metal, or other construction materialsof high thickness and tensile strength. The storage tanks can beassembled relatively easily by welding together steel or metal plates inground-up construction. However, when such storage tanks have outlivedtheir use, they need to be demolished and cut into smaller pieces fortransport to landfill, waste, scrap, or recycling facilities. Demolitionof such storage tanks is a difficult and dangerous task due to the needto take down a very large, heavy structure of high rigidity andstrength.

Currently, a typical tank demotion process requires cutting or punchingentry holes in the tank walls at locations around the tank, thenlaboriously snipping, shearing, cracking, or pulverizing cuts down thetank walls using a hydraulically-operated jaw or shear attachmentoperated on the end of a hydraulic arm of a heavy carrier or excavatorvehicle. As examples, such hydraulically-operated jaws or shears aresold by The Stanley Works, LaBounty Division, of Two Harbors,Minneapolis, under the designation MSD Mobile Shears. However, suchhydraulic jaws or shears can cut in bites of only 6 to 12 inches at atime, making it extremely laborious to make long cuts down tank wallsmany stories in height and repetitively at intervals over hundreds offeet of tank circumference. A typical tank 50 feet in height and 600feet in circumference could take 30 to 40 hours of work using hydraulicjaws or shears to take it down. In some cases, due to volatile residuesof storage material in the tank, the cutting of entry holes in the metaltank walls with flame or electric arc torches cannot be used, making itmore difficult to create starter holes.

It would therefore be highly desirable to have improved equipment and amethod for demolition of large storage tank structures, particularlythose made of steel or metal walls, in a quicker, less labor-intensivemanner, and which is mechanically easy to operate and can also readilymake starter holes in the tank walls as part of the take-down process.

SUMMARY OF INVENTION

In accordance with the present invention, a hydraulically-operatedripper tool is provided for demolition of large tank structures havingtank walls of metal or other rigid construction material. The rippertool has a mounting portion for mounting as an attachment on an end of ahydraulic arm of carrier or excavator equipment so that it can behydraulically reciprocated with a hooking motion over a given range ofrotation, and a ripper blade having a shank portion fixed to themounting portion and a blade portion extending from the shank portionhaving a sharp inner edge extending along a concave curved arc to asharp point providing an inclined angle of attack relative to the shankportion, wherein the sharp point at the end of the blade portionprovides a point of attack for punching a hole into tank walls and theconcave, sharp inner edge provides a shearing force for cutting throughtank walls.

The present invention also encompasses a novel method of using theripper tool on a hydraulic arm of a carrier or excavator to take down alarge storage tank structure for demolition. The ripper blade is mountedby its shank mounting to the end of the hydraulically-operated arm ofthe excavator. The hydraulic arm is movable upward and downward on aboom of the excavator. The ripper blade is movable with a hooking motionby a hydraulic drive of the arm. The hydraulic arm is rotated upward toan upper end of its vertical range, and the ripper blade is positionedso that the point of the blade is aimed in a horizontal direction tomake a forward thrust to punch an entry hole into a top part of the tankwall. The hydraulically-operated arm (and boom) is pulled downward whilekeeping the ripper blade positioned on the vertical cut being made inthe tank wall. As the ripper blade descends through the cut, it isreciprocated up and down in a series of hooking motions so as to apply ashearing force to cut through the metal plate of the tank wall in a“can-opener” fashion. In this manner, a long vertical cut can be rippedinto the tank wall from the top to a lower part of the wall. A series ofvertical cuts can be made in swathes into one side of the tank walls inorder to weaken the side of the tank. The weakened side can then becollapsed inward to bring the top of the tank structure down on thatside. Similar vertical cuts in swathes can be made to collapse the otherside or sides of the tank. Using the ripper tool in this manner, a tank50 feet in height and 600 feet in circumference can be taken down in 3to 4 hours, or in about one-tenth the time it would take to do the sametask with hydraulic jaws or shears.

Other objects, features, and advantages of the present invention will beexplained in the following detailed description of the invention havingreference to the appended drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a perspective view of a preferred embodiment of the rippertool for storage tank demolition in accordance with the invention.

FIG. 2A shows the ripper tool in side view, and FIG. 2B shows a frontview, for greater detail.

FIG. 3 illustrates the novel method of using the ripper tool to takedown a large storage tank structure for demolition.

FIG. 4 illustrates the tank demolition method of the invention in whichthe ripper tool is used to make a series of vertical cuts into one sideof a tank to weaken it.

FIG. 5 shows the step of collapsing the weakened side of the tank tobring the top of the tank structure down on the weakened side.

FIG. 6 shows the collapsing of the other sides of the tank until thetank structure is taken down.

DETAILED DESCRIPTION OF INVENTION

In the following detailed description of the invention, certainpreferred embodiments are illustrated providing certain specific detailsof their implementation. The following example describes a ripper toolused for demolition of a metal storage tank without torch cutting byoperation on a hydraulic arm of a preferred type of excavator equipment.However, it will be recognized by one skilled in the art that many othervariations and modifications may be made given the disclosed principlesof the invention.

FIG. 1 shows a perspective view of a preferred embodiment of the rippertool for storage tank demolition in accordance with the invention. Theripper tool has a mounting portion MM for mounting at the end of thehydraulically-operated arm of the excavator equipment. The mountingportion MM has a pair of thrust plates 10 a, 10 b, having mount bearingholes 11 a, 11 b, and thrust bearing holes 12 a, 12 b formed therein. Asexplained in detail below, the mount bearing holes 11 a, 11 b are usedto mount the tool attachment to the end of the hydraulic arm of theexcavator equipment, and the thrust bearing holes 12 a, 12 b are used toconnect the tool to the thrust piston of the arm hydraulic drive for theattachment so that the ripper tool can be rotated through a hookingrange of motion. The ripper tool has a blade portion including a shankportion SS that is welded to the shank plate 13. The shank plate 13 isbolted to the mounting plate 14 of the mounting portion MM in abutting,rigid contact with each other. The blade portion has a ripper blade BBextending from the shank portion SS with a sharp inner edge EE extendingalong a concave curved arc to a sharp point PP. In this embodiment, thesharp point PP has a sheath element 18 as a replaceable piece thatsleeves onto and fastened to the end of the ripper blade BB. Also, theshank portion SS is made removable from the mounting portion MM tofacilitate replacement when it has become worn or is to be changed.

In this example, a CAT235™ excavator from Caterpillar Inc., of Peoria,Ill., is used having an operating weight of about 95,000 pounds, with anundercarriage of standard track type. The ripper tool has a weight ofabout 4,700 pounds. The maximum vertical height of the excavator'sarm/stick and boom is about 40 feet. The excavator's diesel engine has arating of 250 flywheel hp. The hydraulic system supplies about 250 hp tothe prime mover and implements. The ripper blade is flame cut from T1high-strength alloy plate, which is made of carbon steel and rated for90,000 to 100,000 pounds of tensile strength. However, it can also bemolded or forged in suitable circumstances. The storage tank to bedemolished is about 50 feet high and 600 feet in circumference. The tankwalls are made of welded steel plates of about 0.375 inch thickness atthe top and increasing to about 0.750 inch thickness at the bottom.

FIG. 2A shows the ripper tool in side view, and FIG. 2B shows a frontview, for greater detail. In this example of the tool, adapted for thehydraulic arm of the Cat-235™ excavator, the mount bearing holes 11 andthrust bearing holes 12 in the thrust plates 10 a, 10 b are spaced about20 inches apart, and accommodate 3-inch diameter pins for mounting tothe hydraulic arm end. The mount bearing holes 11 form an angle of 90°to the tip of blade point PP relative to the line between bearing andthrust holes, for applying maximum thrust force to the point. The thrustplates 10 a, 10 b, inner sections, mount plate 14, and shank plate 13 ispreferably formed of high-strength Lo alloy plate, to ASTM 572 GR 50standard. The shank portion of the ripper tool has an ear 15 projectingfrom its upper end that is inserted through a slot in the shank plate 13when the shank portion is welded thereto, and also extends through amatching slot in the mount plate 14 when the shank plate is bolted tothe mount plate 14.

The shank portion SS of the ripper tool tapers from a width of about33.5 inches where it is coupled to the shank plate 13 to about 17.5inches where it extends into the blade portion BB. Preferably, the shankand blade portions are formed from a single, T1 high-strength alloyplate, to ASTM A514 standard. The inner edge of the shank and bladeportions is formed as a sharp edge EE which may have a line thickness of0.188 inch, for example, as compared to a 3-inch plate thickness. Thesharp edge EE can be dimensioned about 3.5 inches in the widthwisedirection (lateral direction in plan view) at the shank and bladeportions, then tapering toward the point PP. The replaceable sheathelement 18 covering the point PP is also fabricated from T1 plate.

The sharp inner edge extends from the shank portion SS along a generallyconcave curved arc of the blade portion BB to the point PP. For example,the curved arc can incline inward from the shank portion about 10° thenform about 130° of concave curvature where it comes to the point PP. Thepoint PP thus forms an inclined angle of attack of about 30° relative tothe shank/mount plate line, or about 45° relative to the axis betweenthe mount bearing holes 11 and the tip of the point PP. The inclinedangle of attack and concave curvature can span a broader range ofangles, depending on the configuration of the hydraulic arm andexcavator equipment.

FIG. 3 illustrates the novel method of using the ripper tool to takedown a large storage tank structure for demolition. The ripper blade BBis mounted by its mounting portion MM to the end of an arm/stick 32articulated on a boom 30 of a carrier or excavator vehicle CAT. The endof the arm stick is coupled by pins through the mount bearing holes 11,and the hydraulic drive 33 for rotating the hook motion of the armattachment is coupled by pins through the thrust bearing holes 12. Inthis manner, the ripper blade BB can be rotated with a hooking motion bythe hydraulic drive 33. The arm/stick 32 is driven by the hydraulicdrive 34 in rotation upward or downward, and the boom 30 is driven byits boom hydraulic drive.

In the tank demolition method illustrated in FIG. 3, thehydraulically-operated arm 32 is rotated upward on the boom 30 to anupper end of its vertical range and the ripper tool BB is rotated upwardto an upper end of its hooking range by the hydraulic drive 33 so thatthe point PP of the blade BB is aimed in a generally horizontaldirection to make a forward thrust at the tank wall line to punch anentry hole into a top part of the tank wall. The hydraulically-operatedarm 32 and boom 30 are pulled downward as the excavator is edgedbackwards from the tank wall line to keep the ripper blade positioned onthe vertical cut being made in the tank wall. A series of ripper bladepositions A, B, C corresponding to the excavator positions A, B, C isshown in the figure. As the ripper blade descends through the cut, it isreciprocated up and down in a series of hooking motions (indicated bythe series of arrows over the ripper blade positions in the figure) soas to apply a shearing force to cut through the metal plate of the tankwall in a “can-opener” fashion. In this manner, a long vertical cut canbe ripped into the tank wall from the top to a lower part of the wall.

As illustrated in FIG. 4, the tank demolition method can be performedquickly and efficiently using the following series of steps. First, aseries of vertical cuts are made in swathes into one side of the tankwalls in order to weaken the side of the tank. The cuts are made about 2to 3 feet apart in this example, but can be farther apart for tanks thatare smaller and/or have thinner wall thicknesses. As shown in FIG. 5,the weakened side of the tank can then be collapsed inward to bring thetop of the tank structure down on that side. Similar vertical cuts inswathes can be made to collapse the other side or sides of the tank,until the tank has been taken down, as shown in FIG. 6. Using the rippertool in this manner, a tank 50 feet in height and 600 feet incircumference can be taken down in 3 to 4 hours, or in about one-tenththe time it would take to do the same task with hydraulic jaws orshears. Once the tank structure has been taken down to the ground, itcan be cut up into smaller pieces with hydraulic shears or other cuttersfor transport away. The cuts in the tank walls can be made to suitablewidths to facilitate cutting into smaller pieces and transport away fordisposal.

In summary, the present invention provides a hydraulically-operatedripper tool that can be used for demolition of large tank structures ina much shorter time. The ripper tool has a sharp point for punchingentry holes into the tank walls, so that no torch cutting of entry holesneeds to be used, particularly where there might be volatile residuesleft in the tank. The ripper tool has a concave, sharp inner edge and isoperated by the hydraulic arm in reciprocation so as to provide ashearing force to cut quickly through metal walls in “can-opener”fashion. The ripper tool facilitates making long vertical cuts into thetank wall from top to bottom, so that a series of vertical cuts can bemade to weaken a side of the tank and allow the top of the tankstructure to be brought down. Using the ripper tool in this manner, alarge tank can be brought down in about one-tenth the time it would taketo do the same task with hydraulic jaws or shears.

It is understood that many modifications and variations may be devisedgiven the above description of the principles of the invention. It isintended that all such modifications and variations be considered aswithin the spirit and scope of this invention, as defined in thefollowing claims.

1. A hydraulically-operated ripper tool for attachment on a hydraulicarm of carrier or excavator equipment for use in demolition of metalwalled structures, comprising: (a) a mounting portion for mounting on anend of a hydraulic arm of carrier or excavator equipment such that thetool can be reciprocated by the hydraulic arm with a hooking motion overa given range of rotation, and (b) a ripper blade having a shank portionfixed to the mounting portion and a blade portion extending from theshank portion having a sharp inner edge extending along a concave curvedarc to a sharp point, wherein the sharp inner edge is inclined inwardalong the curved arc from the shank portion about 10° then forms about130° of concave curvature where it comes to the sharp point, therebyproviding an inclined angle of attack relative to the shank portionwhich is capable of generating a shearing force on an object of attackwhen the ripper blade is pulled in a downward direction from the shankportion, and wherein the sharp point at the end of the blade portionprovides a point of attack for punching a hole into a metal wall, andthe concave, sharp inner edge is capable of providing a shearing forcefor cutting through the metal wall.
 2. A hydraulically-operated rippertool according to claim 1, wherein said mounting portion has a pair ofthrust plates provided with mount bearing holes to mount the tool to theend of the hydraulic arm, and thrust bearing holes to connect the toolto the arm's hydraulic drive.
 3. A hydraulically-operated ripper toolaccording to claim 1, wherein the sharp point is provided with a sheathelement that sleeves onto and is fastened onto the end of the bladeportion.
 4. A hydraulically-operated ripper tool according to claim 2,wherein the mount bearing holes form an angle of 90° to the tip of bladepoint relative to a line between the mount bearing and thrust bearingholes.
 5. A hydraulically-operated ripper tool according to claim 1,wherein the shank and blade portions are formed from a single, T1high-strength alloy metal plate.
 6. A hydraulically-operated ripper toolaccording to claim 1, wherein the point forms an inclined angle ofattack of about 30° relative to a transverse direction of the shankportion.
 7. A hydraulically-operated ripper tool according to claim 2,wherein the point forms an inclined angle of attack of about 45°relative to an axis between the mount bearing holes and the tip of thepoint.
 8. A hydraulically-operated ripper tool according to claim 1,wherein an assembly of the mounting portion and ripper blade weighs in arange of about 4,700 pounds.